


Christmas Cookie Madness

by EvergreenEmerald



Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell, Christmas Cookies, Christmas Fluff, Destruction, Established Relationship, F/M, First Christmas, Implied Sexual Content, Marriage, Papyrus and sugar should never mix, Swearing, Underfell Papyrus, Underfell Sans, kitchen disaster
Language: English
Status: Completed
Published: 2016-12-26
Updated: 2016-12-26
Packaged: 2018-09-12 08:49:49
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,161
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/9064771
Author URL: https://archiveofourown.org/users/EvergreenEmerald/pseuds/EvergreenEmerald
Summary: It's your first christmas married with Sans and Papyrus and you decide to go all out with christmas decoration, gifts, and plan a small get together with all the other monsters. You are making christmas themed desserts when you find out that Papyrus never had a sugar cookie before... and for good reason. who knew one Santa cookie could do so much damage?





	

**Author's Note:**

> Merry Christmas!(Even though it's a couple hours late) I had this idea earlier when one of the little kids at my house is banned from cookies because he is known to go wild and destroy everything insight. I instantly thought about uf!Papyrus and thought this would be a good one-shot.

“I can’t believe you thought that was a good fuckin idea!” Sans grumbles from the passenger seat as you drive Papyrus’ convertible.

 

You groan as Sans continues to lecture you on your poor life choices. “I am sorry okay! How many times do I have to say it?!” You are looking around the streets, listening for any screams.

 

“You just fuckin had to get into the fuckin holiday spirit. ‘It’s Christmas, we are supposed to make these pansy ass cookies that are fully loaded with sugar that have even more sugar poured on top’!” Sans yells even louder, growling at you as he mocked you. “‘Oh, I have another brilliant shitty idea, lets feed one to The Great and Terrible Papyrus who goes on a hyper fuckin rampage whenever he eats sugar!’ Yeah, really lovin the holidays doll face. Now we are out here looking for my brother’s sugar loaded ass while my balls freeze off.” He grumbles in his seat as he looks for Papyrus on the other side of the street.

 

You grip tighter on the steering wheel. “Oh don’t worry honey, your balls aren’t freezing. I left my purse at home.”

 

It took Sans a moment before he turned to you with this expression that spelled ‘not amused’. “Oh hah hah, shut up doll, only I make jokes around here.” You roll your eyes.

 

“PAPYRUS! WHERE ARE YOU!?” You shout out the window.

 

Sans follows your lead, poking out half his body out the window. “Yo Boss! If you don’t show up in five seconds, I’ll pour mustard on your shit!”

 

You sigh. “I really am sorry. I didn’t know… I just thought it would be something fun for us to do…”

 

“Yeah… I get it…” Sans reached over and patted your knee, his way of saying sorry.

 

“Who would have thought a Santa cookie would cause so much trouble…”

 

* * *

 

~ Few Days Earlier ~

 

“Papyrus! Can you help me with unloading the car?” You opened the front door, hands full of bags.

 

“SISTER! WHAT IS THE MEANING OF ALL THIS?” Papyrus paused the TV as he watched you drop everything onto the floor.

 

You stood up and straightened your coat. “Well, this is our first Christmas together as… a family, so I thought I'd go all out. I noticed that we didn’t have any Christmas decorations so I went out and bought a lot, along with a fake Christmas tree with fancy lights already in it.” You feel yourself blush as you fiddle with your wedding ring. You still can’t believe that you are actually legally married to your long time monster lover. You look over at Papyrus, who was making a confused look. “Is something wrong?”

 

“SISTER, I AM UNSURE ON HOW TO INFORM YOU OF THIS BUT …WE DO NOT ACTUALLY CELEBRATE CHRISTMAS…ANYMORE.” Papyrus scratched his skull.

 

“Huh? But Sans and I had Christmas together before, even with my family when we first got engaged…” Papyrus stands up and makes his way out the door.

 

“WELL, WE DID HAVE CHRISTMAS IN THE TRADITIONAL SENSE AS BABY BONES, BUT LIVING IN THE UNDERGROUND… WE COULDN’T BE SEEN SHOWING AFFECTION AND LOVE FOR EACH OTHER. NOT LIKE I CARED THOUGH.” Something in his voice tells you otherwise, but you learned not to push for Papyrus to share his feelings. “WHAT THE FUCK?”

 

Papyrus’ jaw dropped as he took sight of the car. There were boxes and bags overflowing in the backseat and trunk, there was a large box strapped to the roof as well that was wider than the car. “I also went grocery shopping and a little Christmas present shopping. Heh heh, I may have gone a little overboard…”

 

“IF SANS HAD HALF THE ENERGY AND STAMINA YOU HAD, HE WOULD ALMOST BE ON THE SAME LEVEL AS I, THE GREAT AND TERRIBLE PAPYRUS.” He grabbed the big box on top of the car, carrying it with ease on his back. It was a brand new mattress for you and Sans’ room.  It is kind of a present for you too, since you sleep on that beaten down mattress too and it has been killing you.

 

“Also, I ran into Toriel and Frisk, we thought it would be nice to have everyone together again so… I may have invited them over for Christmas dinner, and they may have invited Undyne, Alphys, Mettaton and his cousin, and Asgore as well… and I want to invite Grillby as a thank you for always dealing with Sans.” You sheepishly pick up a few more bags and follow Papyrus back into the house.

 

He puts the box down in the living room and slowly turns to you in horror. “YOU INVITED… THE ROYAL FAMILY, THE DEMENTED KILLER, THE PSYCHOTIC SCIENTIST, AND A SOCIOPATHIC SELF-CENTERED ROBOT… TO OUR HOUSE TO CELEBRATE CHRISTMAS TOGETHER….I CAN’T TELL IF YOU ARE JUST FUCKING STUPID OR BRAVE. THEN AGAIN, YOU MARRIED MY BROTHER SO I AM LEANING TOWARDS STUPIDITY.” You wave off the insults, you know the edgy marshmallow doesn’t actually mean to insult you; it’s just his way of showing how he is worried.  

 

“It’ll be fine, I got a large turkey, chicken, ham, ingredients for green bean casserole, cranberries, mash potatoes, stuffing, ten feet of Italian bread, some veggie sides, veggie and fruit platters, apple cider, spiced apple cider, spiked apple cider, red and white wine, rum, eggnog, eggs for deviled eggs, spinach dip, spicy cheese dip, popcorn, and stuff to make Christmas rum cake, cheese cake, and Christmas cookies. Oh, and I got a whole bunch of pasta, ten bags of cheese, and that fancy sauce you like, all from that authentic Italian grocery store.” You hold up a bag that is full of different types of pasta noodles.

 

Papyrus snatched the bag from you and looked inside. “THERE ARE EVEN SOME IN THE SHAPE OF CHRISTMAS SYMBOLS IN HERE…” Papyrus’ cheeks dusted red, his sharp teeth fighting a grin from forming, but his eyes were sparkling. That’s how you know you won him over.

 

“Yeah, and they also have Christmas recipes on them, so you can serve them as side dishes as well, so you could make spaghetti and lasagna and then even more pasta dishes for everyone to enjoy.”  You grin cunningly; this was your ticket to letting Papyrus have the party. You know Sans wouldn’t have a problem either, but you did buy multiple types of mustard in super-sized bottles just in case.

 

“THIS PARTY MAY NOT BE THAT BAD AFTER ALL IF I AM PREPARING FOOD AS WELL THEN. MAYBE MY DISHES CAN SALVAGE THE DISASTERS I KNOW THAT WILL COME BECAUSE OF THIS. NYEH HEH HEH!” You smile up at your brother-in-law as he struck a pose.

 

“I am so happy you are willing to save me. Let's finish getting everything out of the car and decorate the house before Sans gets home from work.”

 

* * *

 

“I can’t believe you got Boss to do this and how much you bought. I know your job pays well, but damn sweetheart, you bought a shit-ton.” Sans snuggles into you on the couch as you watch the Christmas tree twinkle, in sync with Christmas music.

 

You get comfortable in his lap, leaning your back against his chest. “The pasta bribe really helped. Should have seen his eye sockets sparkle.” Sans hummed as he dug his fingers in your hips under your shirt.

 

“I bet it’ll be fine baby, you did a good job preppin for it and buying all those gifts.” You feel his hands wander; his fangs graze your neck before he takes a long lick. Your toes begin to curl. “Mind if I unwrap you?”

 

“Oh now he asks for permission.” Sans chuckles as he unties your pajama bottoms.

 

* * *

 

~Christmas Morning~

 

You are humming in the kitchen. It is Christmas morning and you are baking cookies. The rum cake is on the cooling rack, the cheesecake is resting in the fridge, now you just have the easiest part left, making gingerbread and sugar cookies. Sans is testing out the new mattress you got, he fell asleep the instant his head landed on the pillow. Papyrus was in the living room watching one of the MTT movies that you gave him. He acted like it wasn’t something he actually really wanted, but from the blush on his cheeks, you knew he was excited. You also got him a pasta maker so he can make homemade pasta whenever he wants. You got Sans some new sweat pants that look like jeans and a clapper for the bedroom, so he doesn’t have to get up to turn off the lights, just clap. He was so proud that you gave him things that would allow him to be lazier than he already is. He installed it almost instantly and played around with it for twenty minutes of clapping. Papyrus grumbled about how you weren’t helping Sans break his terrible habits, but Sans was so happy that it was worth it to you. Plus, it makes it easier when you guys are too tired after some very physical activities in the bedroom… heh heh, you are smirking to yourself,  you have one more gift for Sans, but that is going to be later tonight when everyone is asleep. “SISTER! WHAT IS THAT SMELL?” Papyrus’ loud voice woke you from your daze. “WHAT IS WITH THAT SMILE? WERE YOU HAVING IMPURE THOUGHTS OF MY BROTHER AGAIN? GROSS.”

 

“Was not…” You shift your eyes to the left.

 

“LIAR. I AM NOT OBLIVIOUS TO YOUR CANOODLING. I MAY NOT HAVE EARS, BUT I CAN STILL HEAR.” You instantly blush and start focusing on frosting the cookies again. “ANYWAYS, WHAT IS THAT SMELL?”

 

“Um, the cookies? Have you never had sugar cookies before?” You raised an eyebrow at him.

 

Papyrus shakes his head. “FOR SOME REASON SANS NEVER LETS ME HAVE ANYTHING LIKE THAT, PLUS THE ONLY PERSON AROUND WHO MADE TREATS LIKE THIS IS AN EIGHT-ARMED BITCH WHO OVERCHARGES HER SHIT. I WAS ALSO TOO BUSY WITH MY GUARD DUTIES AS SECOND IN COMMAND.”

 

You feel your heart hurt at that. They barely celebrated holidays, suffered through the Underground, and never even got to eat cookies to comfort them. “Well Papyrus, you now can eat as many cookies as you want. I’ll be happy to make you more anytime in the future; it doesn’t have to be just Christmas.” You finish frosting a Santa cookie and hand it over to Papyrus.

 

You laugh as you watch Papyrus turn the cookie so he could bite Santa’s head off first. He takes a bite and chews slowly. “THIS… IS REALLY GOOD- I MEAN, IT’S NOT BAD, I MAY NEED TO EAT MORE TO FULLY EVALUATE IT.” He shoves the rest of the cookie in his mouth as Sans walks into the room.

 

Sans is rubbing one of his eye sockets as he sleepily walks in. “Hey babe, can you get me some mustard?” He looks up and his eye lights vanish instantly. “Boss… what are you eating?”

 

“THESE SUGAR COOKIES YOUR HUMAN MATE MADE.” Papyrus picks up another one, this one shaped like a present.

 

Sans teleports over to Papyrus and slaps the cookie out of his hand. “Sans?”

 

“Why would you let him eat these!?” Sans looks at you worriedly, skull sweating.

 

“It’s just one cookie Sans, I don’t see why he can’t have-” You are cut off by the sound of Papyrus chuckling.

 

Sans looks at Papyrus and his one eye lights up with red magic. “Shit.”

 

“NYEH HEH HEH HEH HEH HEH HEH HEH HEH!!!!” Sans teleports over to your side of the counter and pulls you down to the ground, covering you with his body. A magic wave pulses through the air. Cookies and kitchen tools go flying. You hear loud stomps around the house, glass shatter, and wood crack. The room is silent. You and Sans pull apart and slowly peak over the counter. There is cookies and frosting all over the walls, most of the cookies didn’t survive, the rum cake is on the floor, and there is even a spoon sticking the wall on the other side of the room.

 

“What the fuck was that?” You pick a limb of a gingerbread man out of your hair.

 

“That was The Great and Terrible Papyrus on a sugar high…” Sans stands up and you follow him out of the room. The living room is destroyed, it looks like Papyrus stomped through the glass coffee table and the front door was broke in half. “Shit… how much sugar was in those things? This is why I didn’t allow him any sugar as a kid and now…. Fuck, he broke the front door. Why the fuck did you give him a cookie?” Sans turns to you furiously.

 

“He said he never had one before, I just thought it would be nice-”

 

“Um… hello?” Toriel poked her head inside the house, Frisk and Flowey behind her.

 

“H-hi Miss Toriel…” You stammer.

 

Sans groans at her. “Heya old lady.” She glares at Sans as they tip toe into the room.

 

“We saw Paps run down the street as we pulled up to the house. What happened?” Frisk asked worriedly.

 

Sans glares at you. “Someone fed him some sugary crap and now he is out on a rampage on an unsuspecting world.”

 

“Ugh! I’m sorry!” You throw your arms in the air. You walk over to where Papyrus’ keys are hanging. “Lets go find him before he destroys a building. Toriel, do you mind cleaning the kitchen and starting cooking the meats for me?” Toriel nods at you as you slide a coat on. “You coming Sans?”

 

“Ugh… fiiiiiiinnnne.” Sans throws his head back as he follows you out the doorway.

 

* * *

 

~ Now ~

 

“It’s been an hour…” You grumble as you look around.

 

“Hey… look.” Sans points to a group of parents rushing their kids out of a park. “Anyone that can clear a park like that is either Undyne or Papyrus.”

 

You agree and park the car by the park. You and Sans run out and head to the park, stopping a parent. “Excuse me, have you seen a really tall skeleton-”

 

“Yes, he is the reason we are leaving the park.” They said angrily at you.

 

Sans growls at them defensively. “He is also the reason why you shouldn’t give your kids sugar, and my little brother.”

 

“Well your little brother is disturbing the peace.” They spat, pushing their child behind them.

 

Sans looks like he is about to argue with them when you grab his arm. “We do not have time for this bullshit. Lets get Papyrus and go home.”

 

“Fine…” Sans sighs and lets you pull him into the park, but he flips off the parent as you do.

 

You are looking around, weaving through the parents. Lo and behold, there is Papyrus standing on top of a children jungle gym. “NYEH HEH HEH, I AM NOW THE RULER OF THIS PLANET AND YOU ARE ALL NOW MY SUBJECTS! BOW TO THE GREAT AND TERRIBLE KING PAPYRUS! NYEH HEH HEH HEH HEH HEH HEH HEH HEH HEH!” You and Sans stare up at him, jaws dropped in shock.

 

“What…”

 

“The actual…”

 

“Fuck…”

 

“How do we get him down?” You look to Sans who just shrugs. “Okay then…” You make your way over to Papyrus and yell up at him. “Papyrus! Honey, can you please come down?”

 

“Oh yeah, please is so gonna help.” Sans rolls his eye lights at you. “Boss, get your ass down here right now!”

 

Papyrus glares down at Sans. “NEVER! YOU CAN’T TELL ME WHAT TO DO! I AM THE KING! NYEH HEH HEH!”

 

Papyrus continues to cackle as you and Sans smack your foreheads. “What are we supposed to do? I’m not going up there.”

 

Sans shrugs. “I guess we are goin to have to wait for it get out of his system. I’m surprised he is still on his sugar high. He had the cookie over an hour ago; it should be out of his system by now.” Right on cue, Papyrus’ laughs are starting to die down and he sways on his feet. “Oh shit…” Papyrus tips over and falls backwards, Sans just barely catches him with his magic and lowers him to the ground in front of you two.

 

“Nice catch babe…” You bend down to check on Papyrus, he is sleeping soundly with soft little ‘nyeh’s. “This is one hell of a first Christmas…” Sans snorts as he engulfs Papyrus in magic again and you guys leave the park.

 

* * *

 

The rest of the night went well. Papyrus slept most of the night but woke up just in time for dinner that Toriel thankfully helped you with. Sans was able to ‘find’ a door and installed it in. Toriel used her fire magic to heat up the room right away which was wonderful. Frisk and Flowey, much to his displeasure, both curled up to Papyrus while he was asleep with a blanket to absorb some of his warmth. It was absolutely adorable. Everyone had fun, enjoyed the opening of gifts. You never received so many hugs by so many people. You are doing some dishes while others watch one of Papyrus’ movies. Mettaton was ecstatic to find out that Papyrus loved his movies, even though Papyrus denied it heavily and acted like he was angry that Mettaton ruined the DVD cases with his signature. You feel arms wrap around your waist. “Hey babe.” Sans pressed his teeth to the back of your neck.

 

“Hey hon, why aren’t you with everyone in the living room?”

 

Sans snuggles into you, his arms tighten around you. “Just wanted to say sorry for snappin at you. Probably should have told you about Papyrus’ sugar problems before.”

 

“It’s okay… I understand that you were just worried about your brother.” You giggle as you notice a red glow in the corner of you eye.

 

“I w-was not worried about him. Why would I?” Sans tries to deny it, you giggle and turn around to kiss him right between the sockets.

 

“Come on my glowing cherry, lets watch the movie with everyone.”

 

* * *

 

You peek into the bedroom to see Sans getting undressed. You had one last gift for Sans; a very sexy, frilly, see-through red lingerie with a Santa hat on. You tip toe into the room and hug him from behind after he took off his shirt. He jumps a little from your touch. “Geez sweetheart, if I had a heart, you would have given me a heart attack.”

 

“I’m sorry baby; I've been such a naughty girl today.” Sans turns around and his eye lights go out. You chew on your lip as you look at him lustfully.

 

“W-woah…”

 

You grab him by his ribs and pull him against you. “Come over here and unwrap your last Christmas present and fill my stocking.” Sans grins as he reaches around you and claps.


End file.
